1. Field
Example embodiments relate to a pitch control unit, a picker having the pitch control unit, and a test handler having the picker. More particularly, example embodiments relate to a pitch control unit for controlling a picker pitch by linearly moving cylinders, a picker having the pitch control unit, and a test handler having the picker for transferring semiconductor devices under test to a test tray from a customer tray.
2. Description of the Related Art
Semiconductor devices usually undergo various electrical testing processes in a manufacturing process or a packaging process, e.g., an electrical die sorting (EDS) process in the manufacturing process. In general, the electrical testing process may be performed by an automatic test equipment (ATE), i.e., a device under test (DUT) is automatically connected to a test center by a test handler and an electrical test or measurement is conducted on the DUT by the test center.
When a plurality of the DUTs is received in customer trays of a customer stack of the test handler, the DUTs are individually picked up from the customer trays and are transferred into test trays by a picker assembly. Then, a plurality of the test trays is sequentially loaded into a test chamber that may be electrically connected to the test center via a test head. Since the DUTs are picked up individually from the customer trays by the picker assembly, the number of the DUTs that are simultaneously picked up and transferred to the test tray is determined by the number of the pickers.
In a conventional test handler, a device gap between the DUTs of the user tray is different from that of the test tray, thus a picker pitch is necessarily varied corresponding to the device gap of the DUTs as the picker assembly moves between the user tray and the test tray. For that reason, a pitch control unit is installed in the picker of the conventional test handler, so the picker pitch is controlled to increase as the picker assembly moves from the user tray to the test tray and controlled to decrease as the picker assembly moves from the test tray to the customer tray.